Mushroom barbecue smoker



FIG. 1 is a front perspective view of a mushroom barbecue smoker showing my new design;

FIG. 2 is a rear perspective view thereof; and,

FIG. 3 is a side perspective view thereof.

The broken lines depict environment and form no part of the claimed design. 

CLAIM The ornamental design for a mushroom barbecue smoker, as shown. 